环境科学与生态学最新文献

Bromate, a possible carcinogenic byproduct of ozonation, is potentially removed by the ultraviolet (UV)/sulfite advanced reduction process (ARP), with hydrated electrons playing a major role. However, this process becomes less efficient under acidic to neutral pHs and remains limited to the use of conventional mercury UV lamps. To address these issues, a UV-light emitting diode (UV-LED)-based ARP was studied for bromate removal using thiosulfate as an alternative reducing agent and UV-LEDs emitting at 265 nm and 280 nm as a radiation source. The UV-LED₂₆₅/thiosulfate process effectively reduced 100 ± 0.0% of the initial bromate concentration (4.0 μM) at pH 6.4 ± 0.1, following the pseudo first-order rate constant of 1.3 × 10^-2 min^-1. Meanwhile, the UV-LED₂₆₅/sulfite process attained only 11.6 ± 1.4% bromate degradation efficiency. Results of electron paramagnetic resonance and scavenging experiments indicate that hydrated electrons and sulfite radicals derived from the UV-LED₂₆₅/thiosulfate process played a significant role in bromate degradation. The process demonstrated optimal performance within a pH range of 5.8-6.4, with higher thiosulfate doses accelerating the bromate removal efficiency. Furthermore, excessive chloride and bicarbonate concentrations interfered with the bromate removal. Comparable energy consumption (electrical energy per order of 27.4 kWh/m³) with UV/sulfite processes has demonstrated the potential of UV-LED₂₆₅/thiosulfate ARPs for effective bromate degradation, using a sustainable UV radiation source and compatible with acidic ozone-treated water.

Sandy soils present key limitations to sustainable agriculture due to low water retention, poor aggregation, and limited nutrient-holding capacity, motivating the use of amendments to overcome these constraints. This study evaluated zeolite, bentonite, and aluminum hydroxide (Al(OH)₃) at 2, 5, and 10 wt%, with and without biochar, on the physical, chemical, and gas-exchange properties of a sandy soil in addition to an agronomy implication under greenhouse conditions. Results showed that all clay minerals reduced soil bulk density, improved aggregation, and increased available water content (AWC), particularly with biochar (e.g., 10% bentonite + biochar gave the highest AWC, +172%; 10% Al(OH)₃ + biochar produced the lowest bulk density, -12%). Biochar's effects were not always additive, as it moderated chemical shifts by buffering pH and reducing EC. In gas exchange, Al(OH)₃ markedly increased CO₂ emissions (+1833%), and this effect further amplified with biochar (+2346%), while CH₄ fluxes remained negative (uptake). To verify agricultural relevance, millet was cultivated under identical greenhouse conditions. In soil only treatments, all minerals exceeded the control; the best response occurred at 5% Al(OH)₃ (+278%), followed by 5% bentonite (+160%). Increasing to 10% did not add benefit because EC with Al(OH)₃ and wilting point with bentonite rose significantly that inversely affect the plants growth. With biochar, responses increased overall, peaking at 5% bentonite + biochar (+315%) and 5% Al(OH)₃ + biochar (+312%). These results provide practical guidance for selecting amendment combinations to balance water retention, fertility, aeration, and greenhouse gas outcomes.

Pulses of plant resources can influence the spatial aggregation and population dynamics of primary consumers, but the extent to which these effects cascade up the food chain to affect secondary consumers remains poorly understood. Mast fruiting events in Southeast Asian dipterocarp forests, for example, are known to impact a wide range of bird and mammal granivores, but it remains unclear whether the predators of these vertebrates are indirectly affected by seed production. Here, we assess bottom-up effects of masting on a suite of primary and secondary consumers in a tropical rainforest in Borneo, using structural equation models to characterize a network of frugivore/granivores and carnivores. The models were parameterized using 10 years of camera trap and seed availability data collected between 2013 and 2024, spanning two major masting events. These models also account for an outbreak of introduced disease (African swine fever) and the reduced abundance of human visitors in the forest during the COVID-19 pandemic. Dipterocarp seed availability was correlated with the intensity of local site use by omnivorous Malay civets (Viverra tangalunga) and bearded pigs (Sus barbatus), but not granivorous murid rodents or pheasants. Leopard cat site use was correlated with murid rodents, but not pheasants. These findings suggest that masting in this ecosystem is associated with site use intensity of some large-bodied primary consumers but not smaller granivores, and therefore did not percolate up the food web to influence the predators of these taxa, in contrast to research from temperate masting systems.

Ethylenediaminetetraacetic acid (EDTA), extensively used across multiple industries, has long been discussed for its potential to enhance heavy metal mobility in aquatic systems, with studies yielding contradictory results. This study examines the remobilization of particle-bound lead from suspended particulate matter (SPM) in the Innerste River (Lower Saxony, Germany), which is affected by historical mining and known for substantial Pb contamination. Using real river water containing its native SPM to preserve the chemical matrix of the system, we assessed Pb partitioning between total and dissolved phases to evaluate EDTA's remobilization potential. Baseline dissolved lead concentrations reached up to 1.8 µg L^-1 (median 0.69 µg L^-1). Across all batch experiments, a measurable increase in the dissolved Pb fraction occurred only at EDTA concentrations far exceeding those measured in the river (0.68-3.8 µg L^-1). Bayesian concentration-response modelling yielded no-effect concentrations (NEC) between 210 and 530 µg L^-1. Complementary speciation modelling showed that shifts in Pb speciation occur only at EDTA concentrations near the experimentally derived NEC values. These findings show that current EDTA concentrations in the Innerste are unlikely to remobilize Pb from SPM. The study also provides a statistically supported NEC estimate based on batch experiments using unaltered river water containing its naturally present SPM. To our knowledge, this is the first application of Bayesian NEC modelling to EDTA-induced Pb remobilization.